Integrated LVRT Technology Based on Stator-side Series Impedance

The low voltage ride-through (LVRT) technology of series impedance on the stator side of the doubly-fed wind induction generator (DFIG) can ensure the low voltage ride-through performance of the DFIG, and at the same time provide reactive power to the grid during the fault period to support the voltage. Putting impedance on the stator side during the fault can reduce the transient impact of the unit and shorten the transient transition process of the unit, but when the voltage drop is small, the input impedance will aggravate the transient impact of the unit, increase the oscillation of the flux, and affect the active and reactive power output of the unit. Based on the above research, a comprehensive LVRT technology is proposed to use the inverter feedforward compensation control when the voltage drop degree does not reach the input threshold, and when the voltage drop degree is greater than the input threshold, the inverter control is used to control the inverter and the series impedance on the stator side. The simulation results show that the proposed method can ensure the low voltage ride-through performance of the fan in the event of a fault, and at the same time, when the voltage drop degree is greater than the threshold, it can cooperate with the series impedance on the stator side to improve the fault operation ability of the unit.